Hyperosmolality dilates rat skeletal muscle arterioles: Role of endothelial K(ATP) channels and daily exercise

Michael P. Massett, Akos Koller, Gabor Kaley

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


The purpose of this study was to investigate the mechanism underlying arteriolar responses to hyperosmolality and to determine the effects of daily exercise on this response. Dilator responses were measured in isolated, cannulated, and pressurized skeletal muscle arterioles. Osmolality was increased from ~290 to 330 mosmol/kgH2O by adding glucose, sucrose, or mannitol to the superfusion solution. All three compounds elicited similar changes in vessel diameter, suggesting that this response was due to changes in osmolality. Responses to glucose were abolished by endothelium removal but were not altered in endothelium-intact vessels by superfusion with the nitric oxide synthase inhibitor N(ω)-nitro-L-arginine or the cyclooxygenase inhibitor indomethacin. In endothelium-intact arterioles, responses to glucose superfusion with the ATP-sensitive potassium (K(ATP)) channel inhibitor glibenclamide; however, intraluminal perfusion with glibenclamide nearly abolished the responses to glucose and mannitol. Intraluminal administration of glucose elicited a significantly greater dilation than extraluminal glucose. The response to intraluminal glucose was also inhibited by intraluminal glibenclamide. Four weeks of daily exercise did not significantly alter the responses to hyperosmolality in gracilis or soleus muscle arterioles. These data demonstrate that physiological increases in intraluminal osmolality dilate rat skeletal muscle arterioles via activation of endothelial K(ATP) channels; however, this endothelium-dependent response is not augmented by daily exercise.

Original languageEnglish
Pages (from-to)2227-2234
Number of pages8
JournalJournal of Applied Physiology
Issue number6
StatePublished - 2000


  • Glibenclamide
  • Glucose
  • Microcirculation
  • Potassium channels
  • Skeletal muscle arterioles


Dive into the research topics of 'Hyperosmolality dilates rat skeletal muscle arterioles: Role of endothelial K(ATP) channels and daily exercise'. Together they form a unique fingerprint.

Cite this